The length and variability of the human menstrual cycle.
D000328:Adult; D000367:Age Factors; D005260:Female; D006801:Humans; D008593:Menopause; D008598:Menstruation / Q000502:physiology*; D008875:Middle Aged; D011446:Prospective Studies; D013223:Statistics as Topic; D013997:Time Factors